I realized V0.10 of Exutil - a small utility to batch rename pictures by date sorted names based on Exif date information or by file's date with an integrated thumbnail viewer.
This is _not_ a killer app, but my playground to get familiar with RapaGUI (earlier versions used MUI Royale). V0.10 is the first RapaGUI based release and not finished, but rather a snapshot. Anyway I gave it a go.

At my tryings, I found a few points, which I have noticed:
1. At the thumbnails, in the left window, are the font too tight to the image, e.g. Folders and .info files.
2. The left window is enlarged by using the pull button at the bottom right. At the moment it is so, that in the left field 4 thumbnails are displayed side by side, this window can not widened, but the right part can be widened infinitely. It would be better other way round, for example, at many files, you can displayed, in the left field more files.
3. Undo function, if you renamed something wrong.

I hope you has understood what I mean.
That was my Points by my first try out.

Thanks for the feedback.
The thumbnail area is indeed a bit to small to accomondate the text w/o overlapping the thumbnail, That will be fixed.
For easiness I limited the thumbnail window to 4 rows. A full resizability has advantages and disadvantages. Am undecided whether i keep it like it is or change it.
An undo function is a good idea. At least there is the filenote function integrated (on Amiga & Co) which includes storage of the old file name - a little help if some files get renamed that should have not... But a proper undo - I am thinking about it.

Main improvement: At the thumbnail view each file has an indicator whether Exutil found an Exif date (green line at bottom of the thumbnail) or not (red line at the bottom of the thumbnail).

Also the exif date gets shown via a toast message when clicking on a thumbnail.

The issues above are not addressed yet. This update was just the work of a rather short evening, but I thought to rush it out anyway....
For all Amigaish systems and Windows. Needs the RapaGUI plugin (except the Windows version where it is linked to the binary)